CONTACT ARRANGEMENT WITH CURRENT MEASURING DEVICE

Description

[0001] The invention relates to a contact arrangement on a printed circuit board with two main contact terminals connected via a current-conducting bridge and with a current measuring device for measuring at least the current flowing through the main contact terminals.

[0002] Such contact arrangements are particularly common on power boards used, for example, to switch batteries on and off in commercial vehicles. To prevent electronic malfunctions, the currents flowing through the contacts must be measured. However, each component on a circuit board requires installation space and conductor connections to the other components. Often, the available space on the boards is limited, as their size cannot be arbitrarily increased but must be adapted to a specific installation space in the vehicle.

[0003] EP 2 383 763 A1 relates to a relay with at least one coil and a movable armature which allows or interrupts a current flow via two main contact terminals by means of the magnetic flux that can be generated in the at least one coil, and with a current measuring device for measuring at least the current flowing via the main contact terminals by means of at least one Hall sensor.

[0004] DE 10 2015 218290 A1 relates to a device for measuring an electric current flow, comprising a printed circuit board, a sensor component for detecting magnetic fields, wherein the sensor component is arranged on a surface of the printed circuit board, and a conductive element for conducting the high / medium / low voltage current to be measured.

[0005] EP 0 867 725 A1 relates to a current detector, in particular a current sensor, which is formed by integration with a conductor through which the current to be measured flows.

[0006] US 2017 / 279261 A1 refers to a current measuring device with two or more current sensors. At least two of the current sensors may have different current measuring ranges and different current measuring sensitivities.

[0007] WO 99 / 36928 A1 concerns a circuit breaker with Hall effect sensors.

[0008] The invention is therefore based on the objective of creating a contact arrangement that requires only a small installation space on a printed circuit board.

[0009] The problem is solved by a contact arrangement on a printed circuit board with two main contact terminals connected via a current-conducting bridge, and with a current measuring device for measuring at least the current flowing through the main contact terminals, wherein the current measuring device (15) is arranged between the current-conducting bridge (14) and the printed circuit board. The placement of the current measuring device between the current-conducting bridge and the printed circuit board thus requires no additional installation space for the current measuring device on the surface of the printed circuit board. Also, a [missing text] not included in the claimed subject matter

[0010] Arranging the current measuring device on the back of the circuit board is conceivable; however, this solution also occupies a portion of the circuit board surface, at least on the back side. Therefore, the claimed solution is clearly superior in terms of area consumption.

[0011] Positioning the current measuring device between the current-carrying bridge and the circuit board is the best solution.

[0012] The current measuring device has at least one Hall sensor. The use of Hall sensors for current measurement allows the flowing currents to be measured indirectly, i.e., galvanically isolated, via the magnetic field induced by the current, rather than directly.

[0013] The current measuring device includes a magnetic flux alignment mechanism comprising at least one ferromagnetic body surrounding the main contact terminals and providing a space for the Hall sensor(s). By focusing the magnetic field, the influence of other components on the circuit board that generate magnetic fields can be eliminated. The magnetic flux is concentrated on the Hall sensor(s). The magnetic field within the space provided by the ferromagnetic body for the Hall sensor(s) is particularly strong, resulting in very high accuracy of the current measuring device.

[0014] The ferromagnetic body can preferably be formed from a stack of ferromagnetic surfaces. By dividing the ferromagnetic body into a stack of individual sheets, each of which can be identically shaped, the remanence of the ferromagnetic body can be significantly reduced.

[0015] In this contact arrangement, a fuse is integrated into the conductive bridge. This fuse interrupts the current flow across the bridge when the current exceeds a predetermined maximum value. Particularly when the contact arrangement is part of a circuit for interrupting the connection to a battery, such a fuse can cause the battery to automatically disconnect before more sensitive components are damaged by excessive current spikes. Such a fuse is especially necessary in high-current applications. Therefore, the maximum current values ​​are preferably between 40 A and 500 A.

[0016] The Hall sensor's measurement signal can also be used to switch off the relay. This results in faster and more precise power protection than using a fuse.

[0017] The contact arrangement can also incorporate a microcontroller that can digitally process the current measured by the Hall sensor and transmit it to a vehicle's electrical system.

[0018] Furthermore, it is advantageous to place an elastic buffer body between the current measuring device and the circuit board. The buffer body serves to fix the ferromagnetic body and to protect the Hall sensor from contamination.

[0019] In a particularly advantageous embodiment, the main contact connections are formed by bolts that are attached to the circuit board via a press-fit connection. These press-fit connections can be created by simply pressing the bolts together with the circuit board. Complex wiring and soldering processes are therefore unnecessary. This results in a robust mechanical connection between the bolts and the circuit board.

[0020] Further advantages can be achieved if the bolts have a stepped diameter, with a lower bolt section having a larger diameter than an upper section. In this way, the bolts can simultaneously serve as mounting elements for the current-carrying bridge and the current-measuring device. The current-carrying bridge can preferably rest on the lower bolt sections, and the current-measuring device can be arranged between the lower bolt sections. The step in the bolts between the lower and upper sections thus serves as a support for the current-carrying bridge. The cavity between the lower bolt sections, located beneath the current-carrying bridge, forms the installation space for the current-measuring device.

[0021] For easy mounting and contacting of the bolts forming the termination contacts, the bridge and / or the current measuring device can have through-holes for receiving and contacting the bolts. This allows the current measuring device and the current-carrying bridge to be placed onto the bolts with their through-holes. If the bolts are also threaded, at least in their upper section, the current-carrying bridge and / or the current measuring device can be mechanically fastened to the bolts using a nut, simultaneously establishing a conductive contact with the bolts.

[0022] In a preferred embodiment, the bolts have a rectangular or square lower section and a round, threaded upper section. The current measuring device can then be provided with two rectangular or square openings and mounted onto the lower bolt sections. Subsequently, the current-conducting bridge, which has two round openings, is mounted onto the upper sections and fastened to the bolts using threaded nuts.

[0023] Preferably, the current measuring device can also measure currents in both directions. This expands the connection options of the contact arrangement.

[0024] A preferred embodiment of a contact arrangement according to the invention is described in detail below with reference to the drawing.

[0025] This shows: Fig. 1 a top view of a printed circuit board with a contact arrangement according to the invention; Fig. 2 an enlarged sectional view through the contact arrangement made of Fig. 1 Fig. 3 shows a detailed view of a current measuring device of the contact arrangement. Fig. 1 Fig. 4 is an exploded view of the current measuring device of the contact arrangement. Fig. 1 .

[0026] Fig. 1 Figure 1 shows a printed circuit board 10 on which a contact arrangement 11 according to the invention is arranged. This arrangement consists of two main contact terminals 12, 13, which are connected to each other via a current-conducting bridge 14. A current measuring device 15 is arranged below the current-conducting bridge 14, which, like the current-conducting bridge 14, is mechanically and electrically coupled to the main contact terminals 12, 13. The current-conducting bridge 14 also carries a fuse 16, which interrupts the current flow through the current-conducting bridge 14 if a predetermined maximum current is exceeded. This protects, for example, a relay 17, which is also arranged on the printed circuit board 11, from damage.

[0027] As the cross-sectional view through the contact arrangement 11 shows Fig. 2 As shown, the main contact terminals 12, 13 are each formed by a bolt that is connected to the circuit board 10 via a press-fit connection. The sectional view illustrates that the main contact terminals 12, 13 each have a lower section 12.1, 13.1 and an upper section 12.2, 13.2, with the lower sections 12.1, 13.1 having a larger diameter than the upper sections 12.2, 13.2. The steps between the sections 12.1, 12.2 and 13.1, 13.2 thus form a support for the current-conducting bridge 14, which is provided with through-holes 14.1, 14.2 by which it can be placed onto the main contact terminals 12, 13.

[0028] Below the current-conducting bridge 14 and the fuse 16 is the current measuring device 15, the more detailed construction of which is described in the Fig. 3 and 4 This is made clear.

[0029] Fig. 3 The current measuring device is shown without a top cover, revealing a ferromagnetic body 18. This body, as well as an elastic buffer body 19 arranged below it with two receiving openings 18.1, 18.2, overlaps the lower sections 12.1, 13.1 of the main contact terminals 12, 13. Fig. 3 It becomes apparent that the lower sections 12.1, 13.1 of the main contact terminals 12, 13 have a square cross-section, while the upper sections 12.2, 13.2 have a round cross-section. In the middle between the two main contact terminals 12, 13, the ferromagnetic body 18 has a central opening 20 in which a Hall sensor 21 is arranged.

[0030] How Fig. 4To illustrate, the ferromagnetic body 18 consists of a multitude of ferromagnetic sheets 22, which are held together by means of rivets 23. The ferromagnetic body 18 is covered from above by a receiving cover 24.

[0031] The setup of the current measuring device 15 is merely an example.

Claims

1. Contact arrangement on a printed circuit board (10) with two main contact terminals (12, 13) connected via a current-conducting bridge (14), and with a current measuring device (15) for measuring at least the current flowing through the main contact terminals (12, 13), wherein the current measuring device (15) has at least one Hall sensor (21), and wherein the current measuring device (15) comprises a device for aligning the magnetic flux, which comprises at least one ferromagnetic body (18) surrounding the main contact terminals (12, 13) and provided with a free space (20) for the Hall sensor(s) (21), characterized in that the current measuring device (15) is arranged between the current-conducting bridge (14) and the printed circuit board, and in that a fuse (16) is arranged in the current-conducting bridge (14), which interrupts the current flow via the bridge (14) when the current exceeds a predetermined maximum value.

2. Contact arrangement according to claim 1, characterized in that the ferromagnetic body (18) is formed from a stack of ferromagnetic sheets (22).

3. Contact arrangement according to claim 2, characterized in that maximum values for the current intensity are between 40 A and 500 A.

4. Contact arrangement according to one of the preceding claims, characterized in that an elastic buffer body (19) is arranged between the current measuring device (15) and the printed circuit board (10).

5. Contact arrangement according to one of the preceding claims, characterized in that the main contact connections (12, 13) are formed by bolts which are fastened to the printed circuit board (10) by means of a press-fit connection.

6. Contact arrangement according to claim 5, characterized in that the bolts have a stepped diameter, wherein a lower bolt section (12.1, 13.1) has a larger diameter than an upper section (12.2, 13.2).

7. Contact arrangement according to claim 6, characterized in that the current-conducting bridge (14) rests on the lower bolt sections (12.1, 13.1) and the current measuring device (15) is arranged between the lower bolt sections (12.1, 13.1).

8. Contact arrangement according to one of claims 5 to 7, characterized in that the bridge (14) and / or the current measuring device (15) have through openings (14.1, 14.2; 18.1, 18.2) for receiving and contacting the bolts (12, 13).

9. Contact arrangement according to one of the preceding claims, characterized in that currents flowing through the main contact connections (12, 13) can be measured in both current directions with the current measuring device (15).